When a human being keeps his body healthy, active oxygen (also referred to as superoxide or oxygen radicals) in the living body is always balanced with super oxide dismutase (SOD), which is an active oxygen scavenging enzyme, and the concentration of active oxygen is maintained at an almost constant value. However, at present, by an unbalanced diet, excessive stress, aging, etc., the formation of SOD is reduced and, on the other hand, by smoking, air pollution, etc., the content of active oxygen is increased.
As a result, thereof, excessive active oxygen exists in the living body which causes various tissue lesions. In particular, in the case of an aged person, the reduction of the SOD activity and the increase of the concentration of active oxygen causes lesions such as articular rheumatism and Behcet syndrome. Also, lipid peroxide formed by active oxygen becomes the main causative agent of modern diseases such as myocardial infarction, cerebral apoplexy, cataract, moth patches, freckles, wrinkles, diabetes mellitus, arteriosclerosis, a stiff neck, feeling of cold, etc.
Furthermore, even in the non-aged, since active oxygen is particularly liable to form at tissues such as skin, which are directly stimulated with environmental factors such as ultraviolet rays, etc., lesions such as the formation of melanine dyes, moth patches, and wrinkles, are liable to occur.
Thus, SOD for scavenging excessive active oxygen which causes the foregoing various lesions has become the subject of scientific and medical attention, and it has been attempted to utilize SOD as medicaments for the prophylaxis and treatment of these lesions or as an additive for cosmetics or foods. However, since SOD is unstable to heat and is inactivated by oral administration, and because SOD is very expensive, no one has yet succeeded in utilizing SOD an active oxygen scavenger.
Under the foregoing circumstances, active oxygen scavengers (including antioxidants having the same function as the SOD enzyme) have been investigated and active oxygen scavengers with a crude drug extract, etc., have been developed. However, such materials must be produced from specific raw materials and hence they are not only expensive but also cannot be stably supplied at present.
As described above, various investigations for scavenging active oxygen in a living body have been actively made since it was recognized that the foregoing various lesions were caused by active oxygen. Also, at present, with an increasing number of elderly and an increasing average life span, public attention is being focused on healthier living into old age. Additionally, from a viewpoint of a beauty treatment, active oxygen scavengers also have become the object of much public interest.
Accordingly, it has been desired to develop an active oxygen scavenger which is safe for the human being, inexpensive, excellent in its effect of scavenging active oxygen which causes various lesions as described above, can be easily produced, and also can be stably supplied.